The proposed studies would allow extensive evaluation and development of technetium-99m stannous pyrophosphate (99mTc-PYP) techniques for acute infarct sizing in patients, the further development of noninvasive means of measuring total and segmental ventricular ejection fraction and ventricular wall motion alterations in patients with ischemic heart disease and provide for the additional development of noninvasive techniques for both "hot spot" and "cold spot" myocardial imaging estimates of infarct size. In addition, the proposed studies would allow for the development of additional new means of radionuclide sizing of infarcts, the evaluation of additional possible means of identifying injured myocardial areas during myocardial ischemia and infarction, the development of animal models of unstable angina pectoris and an assessment of the feasibility of using antibodies developed in our laboratory against the myocardial specific CK-MB isoenzyme and human heart myoglobin for myocardial imaging. In addition, these studies would allow us to attempt to develop means of identifying the presence or absence of collagen using radionuclide techniques as a potential tool for quantitating the amount of scar tissue in hearts of experimental animals and man with ischemic heart disease. Altogether these studies performed in both clinical and experimental animal settings of myocardial ischemia and infarction should provide for considerable additional developments of noninvasive radionuclide techniques for sizing myocardial infarctions, assessing the functional impact of infarct size on ventricular performance and attempting to develop new means of identifying injured and/or scarred myocardium.